A web of material, such as, for example, a web of fabric to be imprinted, or such as a paper web, is imprinted in each printing group of a press that includes several printing groups. Following their passage through the dryer, the webs are combined into a strand, which is divided into individual groups, stacks or batches.
Customarily, the imprinted webs are conducted out of the printing groups of such a press, which printing groups are placed aligned in a first direction. The web is conducted in a direction which extends in a plane defined by this first direction and a vertical line.
This method of guiding the web raises a number of problems. If it is desired to assign a separate dryer to each printing group, for drying the web imprinted in that printing group, the option basically exists to arrange the dryer vertically above the printing group in an extension of the printing group. The result is that extremely high buildings are required for the placement of such a printing press with its included drier. If, on the other hand, it is decided to conduct the webs horizontally through the drying devices, an arrangement results in which the dryers are placed between the printing groups. Therefore, the press has a very great length in the alignment direction. This leads to greatly different web lengths between the individual printing groups and the folder, so that the printing groups must be operated with a large phase offset in order achieve a correct position of the webs, with respect to each other, at the folder.
Although a more compact construction could possibly be achieved by the provision of a common dryer, through which the webs from all of the printing groups are conducted together, this possible solution has the disadvantage that, depending on the placement of the dryer with respect to the printing groups, webs must be conducted between the printing group in which they were printed, and the dryer over long distances. These webs must thus be supported, or must be rerouted several times. In the course of this web support or rerouting, smearing of the not yet dry ink, due to contact of the web with the deflection rollers or the support rollers can occur. Such smearing results in a loss of quality of the printed products.
DD 58 311 discloses a rotary printing press. A dryer is placed downstream of each printing group, and several folders are also provided.
DE 40 12 396 A1 and DE 44 08 027 A1 both show web-fed printing presses with dryers and folders. The axes of rotation of the folding cylinders of the folder extend parallel with the longitudinal direction of the dryer.
EP 888 887 A2 discloses a rotary printing press with several printing towers and several folders. The axes of rotation of the folding cylinders extend parallel with respect to the axes of rotation of the printing cylinders.
A printing press with several printing groups, which are arranged in the axial direction of the cylinder shafts, is known from DE 198 806 C. An inlet of the formers is arranged transversely with respect to the printing cylinders.